A majority of homes and many commercial buildings have a wooden structural frame, wooden interior members and often, have full at least partial wooden or cellulose based exteriors. In many ways, wood is an ideal construction material. It is in plentiful supply, relatively inexpensive and easily worked. Properly cared for, wooden buildings can last for centuries. However, in locales where subterranean termites live and breed, proper care can be difficult to achieve. These termites must have access to water on a regular basis, so that their ideal environment has wood and moisture in close proximity. In a building, this will be anywhere moist soil lies in the proximity of potential termite access to wood. Thus, in construction on a concrete slab, every penetration of the slab by a water line or drain becomes a point of potential termite access. Chlordane, a relatively inexpensive chemical, which provided truly long term protection against termites, with one initial application, was available until the late 1980's. After the EPA banned chlordane in 1988, termite control became a much more challenging a problem because of the limited life and efficacy of available termiticides. These termiticides were not only less effective than chlordane but also, far more expensive. Chemical degradation and leaching conspired to make treatment results unpredictable at best and the termite treatment industry struggled through a difficult period as a result of the EPA action. The termiticide art has advanced since 1988 but even so, no available treatment is expected to last for more than five years and annual inspections are recommended in case more frequent treatment is necessary.
Post-construction termite treatments or re-treatments are expensive, labor intensive procedures, wherein holes are drilled every 12″ to 24″ around the perimeter of the building and also adjacent to any problem areas in the building interior, for injection of termiticide. The interior problem areas are usually in bathrooms, kitchens and wet bars, where unsightly holes must be drilled in a ceramic tile or wood floor covering to penetrate the slab foundation. Over-treatment is necessary, since it is difficult to determine the location of termite entry with any precision, and it is difficult to deliver termiticides to the precise entry location in any case. Such termite treatments are necessarily less effective than would be treatment of the underlying soil before pouring the foundation, and can only be considered to be a reliable deterrent for one year.
Various systems for dispensing termiticide in post-construction treatments have been disclosed. In general, these systems teach the injection of termiticide at a single inlet, with perforated piping or a multiplicity of outlet holes arranged for distribution beneath the slab. Significant problems encountered in such systems have been clogging of the outlets by particles of the fill material and soil underlying the slab, and uneven distribution of the termiticide. A multiplicity of perforations will tend to bleed off the termiticide before it has traveled the full length of the pipe. Even when the pipe is not perforated, unless it is set at the proper gradient, termiticide will not flow to the targeted termite entries. These problems can be offset to some degree by flooding the system with an excess of termiticide under sufficient pressure to overcome pressure losses between the inlet and any given termite entry point. Soil permeability varies widely from one locality to the next. In addition, the underlying soil and sand fill at a construction site will be quite different in this regard. As a result, there is no way to judge the amount of termiticide dispensed to any particular area. The termiticide may go into highly permeable sand at some point and never reach deeper into the system. In any event, the surplus volume of termiticide required to simply fill the length of the piping is essentially wasted.
In actual practice, the construction of foundation slabs introduces some problems that have been ignored in prior teachings of the termite treatment art. For instance, post-tensioned slabs, which have come into common usage in recent years, include a grid pattern of reinforcing beams integral to the underside of the slab, which help carry the loads imposed by cable tension forces. These beams break the fill area under the slab into isolated pockets, making post-construction termiticide treatments all the more difficult. Another slab construction detail not addressed in prior art is the treatment of bathtub plumbing leave-outs, wherein a portion of the slab directly beneath a bathtub is blocked out to provide dimensional flexibility for plumbing connections. As a result, termites have access through the leave-out opening from underlying fill to the wooden plate and studs at the back side of the tub.
A first object of the present inventions therefore, is to provide method and apparatus for effective, uniform post-construction dispensing of termiticides. A second object is to reduce the labor and material expenses of re-treatment. A third object is eliminate the waste of materials and adverse environmental potential of over-treatment and yet other objects are to provide means for more effective treatment of post-tensioned slabs and to eliminate floor covering damage incurred in post-construction treatment.